[PATCH 27/27] coresight: etb10: adjust read pointer only when needed

From: Mathieu Poirier
Date: Tue May 03 2016 - 13:35:01 EST


The read pointer (read_ptr) needs to be adjusted only if its value
has gone beyond the length of the memory buffer.

Reported-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
drivers/hwtracing/coresight/coresight-etb10.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 92f942321e1e..4d20b0be0c0b 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -428,7 +428,8 @@ static void etb_update_buffer(struct coresight_device *csdev,
read_ptr = (write_ptr + drvdata->buffer_depth) -
to_read / ETB_FRAME_SIZE_WORDS;
/* Wrap around if need be*/
- read_ptr &= ~(drvdata->buffer_depth - 1);
+ if (read_ptr > (drvdata->buffer_depth - 1))
+ read_ptr -= drvdata->buffer_depth;
/* let the decoder know we've skipped ahead */
local_inc(&buf->lost);
}
--
2.5.0